The main aims of canopy management

To maximise the effectiveness of light interception by vine canopies

  • Present a large canopy surface to the sun
  • Encourage early development of that canopy in the spring
  • Avoid inter-row shading by having a maximum ratio of canopy height to alley width of 1:1

To reduce canopy shading, particularly in the cluster/renewal zone

  • In highly shaded leaves, the rate of respiration outstrips that of photosynthesis, so the leaf consumes rather than produces energy
  • Shade reduces the viability and success of floral initiation in dormant buds, thus causing an imbalance between leaf area and fruit weight leading to Smart’s vegetative cycle.
  • Shaded flowers have lower rates of successful fertilisation and fruit set
  • Shaded berries keep cooler and so do not ripen as well in cool climates
  • Shaded fruit have lower quality flavours and colours, as some of the biochemical reactions that produce these are stimulated by sunlight
  • Shaded fruit and leaves have far greater risks of contracting fungal diseases, especially powdery mildew and grey rot

To produce a uniform microclimate for fruit

To achieve an appropriate distribution of the products of photosynthesis

  • Too much fruit and not enough leaves (over-cropping) will generate poor quality fruit and reduce vine vigour
  • Too many leaves and not enough fruit will cause over-vigorous growth, which will also produce poor quality fruit.

To arrange the locations of individual organs in restricted zones in space

  • This facilitates mechanisation, particularly in pruning, pesticide application and harvesting

The first step in canopy management is diagnosis